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Defect-localized barrier repair process for copper interconnect structures

IP.com Disclosure Number: IPCOM000012832D
Original Publication Date: 2003-May-30
Included in the Prior Art Database: 2003-May-30
Document File: 1 page(s) / 42K

Publishing Venue

IBM

Abstract

Disclosed is an electroless plating method to repair barrier or liner defects in interconnect structures with copper wiring. The method is defect-localized in that it adds new barrier material only to places where Cu is exposed.

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Defect-localized barrier repair process for copper interconnect structures

    Advanced interconnect structures incorporating copper wiring typically use barrier layers to keep Cu out of the inter/intralayer dielectrics and to protect Cu from corrosion. To be effective, these barriers must be continuous and pinhole-free. However the integrity of these barriers can be compromised by thermal cycling as well as by the dielectric etch-back processes needed for fabricating certain air-gap and etch-back/gap-fill interconnect structures.

Disclosed here is a method to repair barrier or liner defects. The method is specifically designed to repair defects that expose Cu, and is intended only for processing schemes in which the liner is exposed by some type of etch-back process. The method is defect-localized in that it adds new barrier material only to places where Cu is exposed.

The invention utilizes an electroless metal deposition process to selectively plug the openings in a defective liner layer. The plating process is selective because the plating solutions will plate on Cu but not on typical liner materials (W, Ta, or TaN). The sample to be repaired (A) is first immersed in a Pd seed layer solution to selectively leave Pd on the exposed Cu, and is then immersed in an electroless plating bath to selectively deposit a barrier repair material (such as Ni-P, Co-P, Ni-W-P, Co-W-P) onto the Pd/Cu. The thickness of the deposited repair material can be controlled by the immersi...